Vehicle radar device and system thereof

ABSTRACT

A vehicle radar device includes a radar control unit, a first antenna array, a second antenna array, a first circuit board and a second circuit board. The first antenna array is communicatively connected to the radar control unit. The first antenna array includes a plurality of first transmitting elements and a plurality of first receiving elements. The second antenna array is communicatively connected to the radar control unit. The second antenna array includes a plurality of second transmitting elements and a plurality of second receiving elements. The first antenna array is a plurality of circuit board antennas and disposed on the first circuit board. The second antenna array is a plurality of circuit board antennas and disposed on the second circuit board.

RELATED APPLICATIONS

This application claims priority to Taiwan Application Serial Number108104305, filed Feb. 1, 2019, which is herein incorporated byreference.

BACKGROUND Technical Field

The present disclosure relates to a vehicle radar device and a vehicleradar system. More particularly, the present disclosure relates to avehicle radar device and a vehicle radar system both including twoantenna arrays.

Description of Related Art

With the rapid developments of advanced driver assistance system (ADAS)and autopilot technology, vehicles are often required to be equippedwith a large number of detection devices or sensing devices to achievethe relevant functions, and thereby the application requirements of thevehicle radar devices are more and more. However, from the vehiclemanufacturer's point of view, the configuration of the large number ofdetection devices is result in increasing the complexity of electronicsystem design and whole vehicle assembling. From the consumers point ofview, if the large number of detection devices of aftermarket (AM) typesare equipped, it would raise the complexity of the human interface orthe connection interface, and the various functions from the multipledetection devices cannot be effectively separated or can causeinterference issues.

Give the above, there is an urgent need for an integrated solution of avehicle detection device or a vehicle radar device, which is featuredwith effectively reducing device number and complexity, in today'smarket.

SUMMARY

According to one aspect of the present disclosure, a vehicle radardevice includes a radar control unit, a first antenna array, a secondantenna array, a first circuit board and a second circuit board. Thefirst antenna array is communicatively connected to the radar controlunit. The first antenna array includes a plurality of first transmittingelements and a plurality of first receiving elements. The second antennaarray is communicatively connected to the radar control unit. The secondantenna array includes a plurality of second transmitting elements and aplurality of second receiving elements. The first antenna array is aplurality of circuit board antennas and disposed on the first circuitboard. The second antenna array is a plurality of circuit board antennasand disposed on the second circuit board. When an angle between thefirst circuit board and the second circuit board is P12, the followingcondition is satisfied: 60 degrees≤P12<180 degrees.

According to another aspect of the present disclosure, a vehicle radarsystem is disposed in a vehicle and includes at least one vehicle radardevice. The vehicle radar device includes a radar control unit, a firsttransceiver unit and a second transceiver unit. The first transceiverunit is communicatively connected to the radar control unit and includesa first antenna array, which includes a plurality of first transmittingelements and a plurality of first receiving elements. The secondtransceiver unit is communicatively connected to the radar control unitand includes a second antenna array, which includes a plurality ofsecond transmitting elements and a plurality of second receivingelements. When an angle between a centerline of a horizontal main lobeof the first transmitting elements and a centerline of a horizontal mainlobe of the second transmitting elements is T12, and an angle between acenterline of a horizontal main lobe of the first receiving elements anda centerline of a horizontal main lobe of the second receiving elementsis R12, the following conditions are satisfied: 0 degrees<T12≤90degrees; and 0 degrees<R12≤90 degrees.

According to another aspect of the present disclosure, a vehicle radarsystem is disposed in a vehicle and includes at least one vehicle radardevice, which is disposed at one of four corners of the vehicle. Thevehicle radar device includes a radar control unit, a first antennaarray, a second antenna array, a first circuit board and a secondcircuit board. The first antenna array is communicatively connected tothe radar control unit. The second antenna array is communicativelyconnected to the radar control unit. The first circuit board is verticalto a horizontal direction of the vehicle. The first antenna array is aplurality of circuit board antennas and disposed on the first circuitboard. The second circuit board is vertical to the horizontal directionof the vehicle. The second antenna array is a plurality of circuit boardantennas and disposed on the second circuit board. When an angle betweenthe first circuit board and the second circuit board is P12, thefollowing condition is satisfied: 90 degrees≤P12<180 degrees.

BRIEF DESCRIPTION OF THE DRAWINGS

The present disclosure can be more fully understood by reading thefollowing detailed description of the embodiment, with reference made tothe accompanying drawings as follows:

FIG. 1A is a schematic view of a vehicle radar device according to the1st embodiment of the present disclosure.

FIG. 1B is another schematic view of the vehicle radar device accordingto the 1st embodiment.

FIG. 1C is a cross-sectional view along line 1C-1C of FIG. 1B.

FIG. 1D is an exploded view of the vehicle radar device according to the1st embodiment.

FIG. 2 is a schematic view of a vehicle radar device according to the2nd embodiment of the present disclosure.

FIG. 3 is a schematic view of a vehicle radar device according to the3rd embodiment of the present disclosure.

FIG. 4A is a schematic view of a vehicle radar system according to the4th embodiment of the present disclosure, disposed in a vehicle.

FIG. 4B is a block diagram of the vehicle radar system according to the4th embodiment disposed in the vehicle.

FIG. 4C is a block diagram of the vehicle radar system according to the4th embodiment.

FIG. 4D is a schematic view of the parameter R12 according to the 4thembodiment.

FIG. 4E is a schematic view of a radiation pattern of first receivingelements according to the 4th embodiment.

FIG. 4F is a schematic view of a radiation pattern of second receivingelements according to the 4th embodiment.

FIG. 4G is a schematic view of the first transceiver units in adetection mode according to the 4th embodiment.

FIG. 4H is a schematic view of the parameters NT2 and WT2 according tothe 4th embodiment.

FIG. 5A is a block diagram of a vehicle radar system according to the5th embodiment of the present disclosure, disposed in a vehicle.

FIG. 5B is a block diagram of the vehicle radar system according to the5th embodiment.

DETAILED DESCRIPTION

The embodiment will be described with the drawings. For clarity, somepractical details will be described below. However, it should be notedthat the present disclosure should not be limited by the practicaldetails, that is, in some embodiments, the practical details isunnecessary. In addition, for simplifying the drawings, someconventional structures and elements will be simply illustrated, andrepeated elements may be represented by the same labels.

FIG. 1A is a schematic view of a vehicle radar device 100 according tothe 1st embodiment of the present disclosure, FIG. 1B is anotherschematic view of the vehicle radar device 100 according to the 1stembodiment, FIG. 1C is a cross-sectional view along line 1C-1C of FIG.1B, and FIG. 1D is an exploded view of the vehicle radar device 100according to the 1st embodiment. In FIG. 1A to FIG. 1D, the vehicleradar device 100 includes a radar control unit 130, a first antennaarray 151, a second antenna array 152, a first circuit board 181 and asecond circuit board 182.

The first antenna array 151 is communicatively connected to the radarcontrol unit 130. The first antenna array 151 includes a plurality offirst transmitting elements 161 and a plurality of first receivingelements 171. That is, the first transmitting elements 161 are firsttransmitting radiating elements, and the first receiving elements 171are first receiving radiating elements. The first antenna array 151 is aplurality of circuit board antennas and disposed on the first circuitboard 181. The second antenna array 152 is communicatively connected tothe radar control unit 130. The second antenna array 152 includes aplurality of second transmitting elements 162 and a plurality of secondreceiving elements 172. That is, the second transmitting elements 162are second transmitting radiating elements, and the second receivingelements 172 are second receiving radiating elements. The second antennaarray 152 is a plurality of circuit board antennas and disposed on thesecond circuit board 182. When an angle between the first circuit board181 and the second circuit board 182 is P12, the following condition issatisfied: 60 degrees≤P12<180 degrees. Accordingly, the first antennaarray 151 and the second antenna array 152, which are two non-coplanarantenna arrays, are advantageous in providing detections with variousdirections and various antenna radiation patterns in accordance withvarious application requirements. Furthermore, the following conditionmay be satisfied: 90 degrees≤P12<180 degrees. Moreover, the followingcondition may be satisfied: 120 degrees≤P12≤150 degrees. In the 1stembodiment, the angle P12 between the first circuit board 181 and thesecond circuit board 182 is 135 degrees.

In FIG. 1C, the vehicle radar device 100 may further include a thirdcircuit board 183. The radar control unit 130 is disposed on the thirdcircuit board 183. Only one of the first circuit board 181 and thesecond circuit board 182 (specifically only the second circuit board 182in the 1st embodiment) is parallel to the third circuit board 183.Accordingly, it is beneficial to the vehicle radar device 100 to achievea compact size. In an embodiment according to the present disclosure,each of a first circuit board, a second circuit board and a thirdcircuit board may be a printed circuit board (PCB), a flexible printedcircuit board, or a ceramic circuit board, but not limited thereto.

An operating frequency of the first antenna array 151 and an operatingfrequency of the second antenna array 152 may be both greater than 10GHz. Furthermore, the operating frequency of the first antenna array 151and the operating frequency of the second antenna array 152 may be bothgreater than 10 GHz and smaller than 300 GHz. Moreover, the operatingfrequency of the first antenna array 151 and the operating frequency ofthe second antenna array 152 may be both 24 GHz+/−5 GHz, 77 GHz+/−5 GHz,or 79 GHz+/−5 GHz. Each of the first transmitting elements 161, each ofthe first receiving elements 171, each of the second transmittingelements 162 and each of the second receiving elements 172 is amicrostrip antenna and has a length smaller than 40 mm. Theaforementioned microstrip antenna may be in a microstrip (strip orrectangular) shape, in a patch shape, in a comb shape, or a microstripslot, but not limited thereto. Furthermore, each of the firsttransmitting elements 161, each of the first receiving elements 171,each of the second transmitting elements 162 and each of the secondreceiving elements 172 is the microstrip antenna and may have the lengthsmaller than 30 mm. Moreover, each of the first transmitting elements161, each of the first receiving elements 171, each of the secondtransmitting elements 162 and each of the second receiving elements 172is the microstrip antenna and may have the length smaller than 20 mm andgreater than 0.2 mm. Therefore, the vehicle radar device 100 being amillimeter wave radar device is advantageous in reducing the number ofthe vehicle radar device 100 and maintaining the same applications andfunctions. The second transmitting elements 162 may be a plurality ofsecond narrow-angle transmitting elements 160 and a plurality of secondwide-angle transmitting elements 166, and the radar control unit 130 isfor switching the second narrow-angle transmitting elements 160 or thesecond wide-angle transmitting elements 166 to operate. The secondreceiving elements 172 may be a plurality of second narrow-anglereceiving elements 170 and a plurality of second wide-angle receivingelements 177, and the radar control unit 130 is for switching the secondnarrow-angle receiving elements 170 or the second wide-angle receivingelements 177 to operate. Therefore, it is beneficial to enlarge thedetection range of the second antenna array 152. In addition, atransmitting circuit communicatively connected to the secondnarrow-angle transmitting elements 160 and a transmitting circuitcommunicatively connected to the second wide-angle transmitting elements166 may be separated or the same one to operate by switching. Areceiving circuit communicatively connected to the second narrow-anglereceiving elements 170 and a receiving circuit communicatively connectedto the second wide-angle receiving elements 177 may be separated or thesame one to operate by switching.

Specifically, the operating frequency of the first antenna array 151 andthe operating frequency of the second antenna array 152 are both about77 GHz or 79 GHz. Relative permittivity at the operating frequency ofthe first circuit board 181, the second circuit board 182 and the thirdcircuit board 183 may be in a range of 2.0 to 4.3. Furthermore, therelative permittivity at the operating frequency of the first circuitboard 181, the second circuit board 182 and the third circuit board 183may be in a range of 2.2 to 3.8. Moreover, a dimension of the firstcircuit board 181 may be at least 19 mm×20 mm×1.4 mm (thickness), and adimension of the second circuit board 182 may be at least 30 mm×20mm×1.4 mm (thickness). The first circuit board 181 and the secondcircuit board 182 respectively include a plurality of through holes 191and 192, which are properly configured and have electrical conductivity.The first circuit board 181, the second circuit board 182 and the thirdcircuit board 183 may be communicatively connected by flexible flatcables (FFC), with the numbers of the conductive wires and the spacesizes according to the demands. The flexible flat cables may be made ofthermoplastic organic LCP (Liquid Crystal Polymers) materials to act ashigh frequency and high speed flexible circuit boards with highreliability. The LCP materials featured with superior electricalproperties are advantageous in being applicable to millimeter wave, andthe LCP materials featured with small coefficient of thermal expansioncan act as ideal package materials for high frequency and high speedproduct. In addition, the first circuit board 181, the second circuitboard 182 and the third circuit board 183 are all disposed in a housing140, which includes a connector 144.

In FIG. 1A and FIG. 1B, each of the first transmitting elements 161 is arectangular microstrip slot antenna, i.e. a radiating slot, which isformed by a slot of a conductive layer on one surface of the firstcircuit board 181 and has a dimension about 3.2 mm (length)×0.5 mm(width). The first transmitting elements 161 are arranged along a widthdirection. For example, the first transmitting elements 161 may bearranged as a slot array antenna of an array of 1×16. A dimension of theslot array antenna formed by the sixteen first transmitting elements 161is about 3.2 mm×17.6 mm. Based on demands, one of the first transmittingelements 161 may be communicatively connected to another thereof by atleast one of a series connection and a parallel connection, and thefirst transmitting elements 161 have at least one feeding port. Each ofthe first receiving elements 171 is a rectangular microstrip slotantenna and has a dimension about 3.2 mm (length)×0.5 mm (width). Thefirst receiving elements 171 are arranged along a width direction. Basedon demands, one of the first receiving elements 171 may becommunicatively connected to another thereof by at least one of a seriesconnection and a parallel connection, and the first receiving elements171 have at least one feeding port. Each of the second narrow-angletransmitting elements 160 is a rectangular microstrip slot antenna andhas a dimension about 3.2 mm (length)×0.5 mm (width). The secondnarrow-angle transmitting elements 160 are arranged along a widthdirection. Based on demands, one of the second narrow-angle transmittingelements 160 may be communicatively connected to another thereof by atleast one of a series connection and a parallel connection, and thesecond narrow-angle transmitting elements 160 have at least one feedingport. Each of the second wide-angle transmitting elements 166 is arectangular microstrip slot antenna and has a dimension about 3.2 mm(length)×0.5 mm (width). The second wide-angle transmitting elements 166are arranged along a width direction. Based on demands, one of thesecond wide-angle transmitting elements 166 may be communicativelyconnected to another thereof by at least one of a series connection anda parallel connection, and the second wide-angle transmitting elements166 have at least one feeding port. Each of the second narrow-anglereceiving elements 170 is a rectangular microstrip slot antenna and hasa dimension about 3.2 mm (length)×0.5 mm (width). The secondnarrow-angle receiving elements 170 are arranged along a widthdirection. Based on demands, one of the second narrow-angle receivingelements 170 may be communicatively connected to another thereof by atleast one of a series connection and a parallel connection, and thesecond narrow-angle receiving elements 170 have at least one feedingport. Each of the second wide-angle receiving elements 177 is arectangular microstrip slot antenna and has a dimension about 3.2 mm(length)×0.5 mm (width). The second wide-angle receiving elements 177are arranged along a width direction. Based on demands, one of thesecond wide-angle receiving elements 177 may be communicativelyconnected to another thereof by at least one of a series connection anda parallel connection, and the second wide-angle receiving elements 177have at least one feeding port. Furthermore, the series connections, theparallel connections and the feeding ports recited in this paragraph canbe configured according to demands and thereby are not specificallyshown in the drawings.

In an embodiment according to the present disclosure (not shown indrawings), a dimension of the first circuit board and a dimension of thesecond circuit board may be greater than the dimensions thereof recitedin the aforementioned 1st embodiment. For example, the dimension of thefirst circuit board may be 38 mm×40 mm×1.4 mm (thickness), the dimensionof the second circuit board may be 60 mm×40 mm×1.4 mm (thickness), and anumber of each of first transmitting elements, first receiving elements,second narrow-angle transmitting elements, second wide-angletransmitting elements, second narrow-angle receiving elements and secondwide-angle receiving elements may be greater than the number thereofrecited in the aforementioned 1st embodiment.

FIG. 2 is a schematic view of a vehicle radar device 200 according tothe 2nd embodiment of the present disclosure. In FIG. 2, the vehicleradar device 200 includes a radar control unit (not shown in FIG. 2), afirst antenna array 251, a second antenna array 252, a first circuitboard 281 and a second circuit board 282. The first antenna array 251 iscommunicatively connected to the radar control unit. The first antennaarray 251 includes a plurality of first transmitting elements 261 and aplurality of first receiving elements 271. The first antenna array 251is a plurality of circuit board antennas and disposed on the firstcircuit board 281. The second antenna array 252 is communicativelyconnected to the radar control unit. The second antenna array 252includes a plurality of second transmitting elements 262 and a pluralityof second receiving elements 272. The second transmitting elements 262are a plurality of second narrow-angle transmitting elements 260 and aplurality of second wide-angle transmitting elements 266. The secondreceiving elements 272 are a plurality of second narrow-angle receivingelements 270 and a plurality of second wide-angle receiving elements277. The second antenna array 252 is a plurality of circuit boardantennas and disposed on the second circuit board 282. An angle P12between the first circuit board 281 and the second circuit board 282 is135 degrees. In addition, the first circuit board 281 and the secondcircuit board 282 respectively include a plurality of through holes 291and 292, which are properly configured and have electrical conductivity.The first circuit board 281, the second circuit board 282 and the thirdcircuit board (not shown in drawings) are all disposed in a housing 240,which includes a connector 244.

Specifically, regarding the vehicle radar device 200 of the 2ndembodiment, except the configurations of the first transmitting elements261, the first receiving elements 271, the second narrow-angletransmitting elements 260, the second wide-angle transmitting elements266, the second narrow-angle receiving elements 270 and the secondwide-angle receiving elements 277 being different from theconfigurations recited in the aforementioned 1st embodiment, the othercharacteristics of the vehicle radar device 200 may be the same as thecorresponding characteristics of the vehicle radar device 100.

In the 2nd embodiment, each of the first transmitting elements 261 is arectangular microstrip slot antenna and has a dimension about 3.2 mm(length)×0.5 mm (width). A number of the first transmitting elements 261is sixteen, and the first transmitting elements 261 are arranged as anarray of 2×8. Based on demands, one of the first transmitting elements261 may be communicatively connected to another thereof by at least oneof a series connection and a parallel connection, and the firsttransmitting elements 261 have at least one feeding port. Each of thefirst receiving elements 271 is a rectangular microstrip slot antennaand has a dimension about 3.2 mm (length)×0.5 mm (width). A number ofthe first receiving elements 271 is sixteen, and the first receivingelements 271 are arranged as an array of 2x8. Based on demands, one ofthe first receiving elements 271 may be communicatively connected toanother thereof by at least one of a series connection and a parallelconnection, and the first receiving elements 271 have at least onefeeding port. Each of the second narrow-angle transmitting elements 260is a rectangular microstrip slot antenna and has a dimension about 3.2mm (length)×0.5 mm (width). A number of the second narrow-angletransmitting elements 260 is sixteen, and the second narrow-angletransmitting elements 260 are arranged as an array of 4×4. Based ondemands, one of the second narrow-angle transmitting elements 260 may becommunicatively connected to another thereof by at least one of a seriesconnection and a parallel connection, and the second narrow-angletransmitting elements 260 have at least one feeding port. Each of thesecond wide-angle transmitting elements 266 is a rectangular microstripslot antenna and has a dimension about 3.2 mm (length)×0.5 mm (width). Anumber of the second wide-angle transmitting elements 266 is sixteen,and the second wide-angle transmitting elements 266 are arranged as anarray of 4×4. Based on demands, one of the second wide-angletransmitting elements 266 may be communicatively connected to anotherthereof by at least one of a series connection and a parallelconnection, and the second wide-angle transmitting elements 266 have atleast one feeding port. Each of the second narrow-angle receivingelements 270 is a rectangular microstrip slot antenna and has adimension about 3.2 mm (length)×0.5 mm (width). A number of the secondnarrow-angle receiving elements 270 is sixteen, and the secondnarrow-angle receiving elements 270 are arranged as an array of 4×4.Based on demands, one of the second narrow-angle receiving elements 270may be communicatively connected to another thereof by at least one of aseries connection and a parallel connection, and the second narrow-anglereceiving elements 270 have at least one feeding port. Each of thesecond wide-angle receiving elements 277 is a rectangular microstripslot antenna and has a dimension about 3.2 mm (length)×0.5 mm (width). Anumber of the second wide-angle receiving elements 277 is sixteen, andthe second wide-angle receiving elements 277 are arranged as an array of4x4. Based on demands, one of the second wide-angle receiving elements277 may be communicatively connected to another thereof by at least oneof a series connection and a parallel connection, and the secondwide-angle receiving elements 277 have at least one feeding port.Furthermore, the series connections, the parallel connections and thefeeding ports recited in this paragraph can be configured according todemands and thereby are not specifically shown in the drawings.

FIG. 3 is a schematic view of a vehicle radar device 300 according tothe 3rd embodiment of the present disclosure. In FIG. 3, the vehicleradar device 300 includes a radar control unit (not shown in drawings),a first antenna array 351, a second antenna array 352, a first circuitboard 381 and a second circuit board 382. The first antenna array 351 iscommunicatively connected to the radar control unit. The first antennaarray 351 includes a plurality of first transmitting elements 361 and aplurality of first receiving elements 371. The first antenna array 351is a plurality of circuit board antennas and disposed on the firstcircuit board 381. The second antenna array 352 is communicativelyconnected to the radar control unit. The second antenna array 352includes a plurality of second transmitting elements 362 and a pluralityof second receiving elements 372. The second transmitting elements 362are a plurality of second narrow-angle transmitting elements 360 and aplurality of second wide-angle transmitting elements 366. The secondreceiving elements 372 are a plurality of second narrow-angle receivingelements 370 and a plurality of second wide-angle receiving elements377. The second antenna array 352 is a plurality of circuit boardantennas and disposed on the second circuit board 382. An angle P12between the first circuit board 381 and the second circuit board 382 is135 degrees. In addition, the first circuit board 381, the secondcircuit board 382 and the third circuit board (not shown in drawings)are all disposed in a housing 340, which includes a connector 344.

Specifically, each of the first transmitting elements 361, the firstreceiving elements 371, the second narrow-angle transmitting elements360, the second wide-angle transmitting elements 366, the secondnarrow-angle receiving elements 370 and the second wide-angle receivingelements 377 is a series-fed patch array (SFPA), and a configuration andat least one feeding port thereof can be configured according to demandsand are not more specifically shown in the drawings. Furthermore,regarding the vehicle radar device 300 of the 3rd embodiment, except theantenna type of the first antenna array 351, the antenna type of thesecond antenna array 352, the dimension of the first circuit board 381and the dimension of the second circuit board 382 being different fromthose recited in the aforementioned 1st embodiment, the othercharacteristics of the vehicle radar device 300 may be the same as thecorresponding characteristics of the vehicle radar device 100.

FIG. 4A is a schematic view of a vehicle radar system 4000 according tothe 4th embodiment of the present disclosure, which is disposed in avehicle 40. FIG. 4B is a block diagram of the vehicle radar system 4000according to the 4th embodiment disposed in the vehicle 40. FIG. 4C is ablock diagram of the vehicle radar system 4000 according to the 4thembodiment. In FIG. 1A and FIG. 4A to FIG. 4C, the vehicle radar system4000 is disposed in the vehicle 40 and includes the vehicle radar device100 recited in the aforementioned 1st embodiment. The vehicle radardevice 100 includes the radar control unit 130, a first transceiver unit141 and a second transceiver unit 142. The first transceiver unit 141 iscommunicatively connected to the radar control unit 130 and includes thefirst antenna array 151, and thereby the first antenna array 151 is alsocommunicatively connected to the radar control unit 130. The secondtransceiver unit 142 is communicatively connected to the radar controlunit 130 and includes the second antenna array 152, and thereby thesecond antenna array 152 is also communicatively connected to the radarcontrol unit 130. In addition, it shall be realized that other vehicleradar device according to the present disclosure can be included in thevehicle radar system 4000.

FIG. 4D is a schematic view of a parameter R12 according to the 4thembodiment. FIG. 4E is a schematic view of a radiation pattern on ahorizontal plane (orientated the same as a horizontal direction of thevehicle 40) of the first receiving elements 171 according to the 4thembodiment. FIG. 4F is a schematic view of a radiation pattern on ahorizontal plane of the second receiving elements 172 (specifically thesecond wide-angle receiving elements 177 thereof) according to the 4thembodiment. Specifically, a schematic view of a parameter T12 is similarto FIG. 4D. In FIG. 4D to FIG. 4F, the first antenna array 151 mayinclude the first transmitting elements 161 and the first receivingelements 171. The second antenna array 152 may include the secondtransmitting elements 162 and the second receiving elements 172. When anangle between a centerline of a horizontal main lobe (i.e. a main lobeon the horizontal plane) of the first transmitting elements 161 and acenterline of a horizontal main lobe of the second transmitting elements162 is T12, and an angle between a centerline C1 of a horizontal mainlobe MLR1 of the first receiving elements 171 and a centerline C2 of ahorizontal main lobe MLR2 of the second receiving elements 172 is R12,the following conditions may be satisfied: 0 degrees<T12≤90 degrees; and0 degrees<R12≤90 degrees. Accordingly, the vehicle radar system 4000 isadvantageous in simultaneously providing detections in differentdirections and maintaining the individual detection accuracy by thefirst antenna array 151 and the second antenna array 152. Furthermore,the following condition may be satisfied: 15 degrees≤R12≤75 degrees.Moreover, the following condition may be satisfied: 30 degrees≤R12≤60degrees. In the 1st embodiment, the parameter T12 is 45 degrees, and theparameter R12 is 45 degrees.

Furthermore, in FIG. 1C and FIG. 4A, the vehicle radar device 100 may bedisposed at one of four corners (i.e. a left-front corner 48L, aright-front corner 48R, a left-rear corner 49L and a right-rear corner49R shown in FIG. 4A) of the vehicle 40. Specifically, the vehicle radardevice 100 is disposed at the left-rear corner 49L as shown in FIG. 4A.The vehicle radar device 100 may further include the first circuit board181 and the second circuit board 182. The first circuit board 181 isvertical to the horizontal direction of the vehicle 40. The firstantenna array 151 is the circuit board antennas and disposed on thefirst circuit board 181. The second circuit board 182 is vertical to thehorizontal direction of the vehicle 40. The second antenna array 152 isthe circuit board antennas and disposed on the second circuit board 182.When the angle between the first circuit board 181 and the secondcircuit board 182 is P12, the following condition may be satisfied: 60degrees≤P12≤180 degrees. Accordingly, the first antenna array 151 andthe second antenna array 152 are advantageous in respectively providingdetections in accordance with various application requirements, reducingthe cost of the vehicle radar system 4000 and simplifying the detectionoptimizing procedure. Furthermore, the following condition may besatisfied: 90 degrees≤P12≤180 degrees. Moreover, the following conditionmay be satisfied: 105 degrees≤P12≤165 degrees. In addition, thefollowing condition may be satisfied: 120 degrees≤P12≤150 degrees.

In FIG. 4E, when a half power beam width (HPBW) of the horizontal mainlobe MLR1 of the first receiving elements 171 is RA1, which is definedby half power markers m1 and m2, the following condition may besatisfied: 75 degrees≤RA1≤180 degrees. In the 4th embodiment, a value ofthe parameter RA1 is 84 degrees. Therefore, a wider detection range canbe provided by the first antenna array 151.

In FIG. 4F, a half power beam width of the horizontal main lobe MLR2 ofthe second wide-angle receiving elements 177 of the second receivingelements 172 is RAW2, which is defined by half power markers ml and m2.In the 4th embodiment, a value of the parameter RAW2 is 118 degrees.

The vehicle radar device 100 may further include the third circuit board183. The radar control unit 130 is disposed on the third circuit board183. Only one of the first circuit board 181 and the second circuitboard 182 (specifically only the second circuit board 182 in the 4thembodiment) is parallel to the third circuit board 183. Accordingly, itis beneficial to the vehicle radar system 4000 to achieve a compactsize. In an embodiment according to the present disclosure (not shown indrawings), it may be only the first circuit board of the first circuitboard and the second circuit board parallel to the third circuit board.

Specifically, besides including the first transmitting elements 161, atransmitting circuit of the first transceiver unit 141 may furtherinclude other elements (not shown in drawings), such as a localoscillator, a phase locked loop (PLL), a power amplifier and etc., whichmay be disposed on the first circuit board 181 or the third circuitboard 183. The local oscillator supporting a wider bandwidth isadvantageous in increasing the distance resolution, due to the distanceresolution of the vehicle radar system 4000 is determined by the signalbandwidth generated by the transmitting circuit. Furthermore, the phaselocked loop is beneficial to the phase control of the local oscillatorso as to minimize the phase noise of the local oscillator. Besidesincluding the first receiving elements 171, a receiving circuit of thefirst transceiver unit 141 may further include other elements (not shownin drawings), such as a low noise amplifier, an image rejection andclutter cancellation circuit portion and etc., which may be disposed onthe first circuit board 181 or the third circuit board 183.Configurations of a transmitting circuit and a receiving circuit of thesecond transceiver unit 142 may be different from but similar to thoseof the first transceiver unit 141, and the elements of the secondtransceiver unit 142 may be disposed on the second circuit board 182 orthe third circuit board 183. Alternately, a transmitting circuit and areceiving circuit (except the first antenna array 151 and second antennaarray 152 thereof, respectively) may be both switched to be used by thefirst transceiver unit 141 or the second transceiver unit 142.

In addition, the first transceiver unit 141 and the second transceiverunit 142 are configured to generate FMCW (Frequency Modulated ContinuousWave) triangular waveform signals. After the first transceiver unit 141and the second transceiver unit 142 receive a plurality of echo signals,the radar control unit 130 performs a FFT (Fast Fourier Transform) stepto obtain a beat frequency and a Doppler shift data of a target object(or a target vehicle), and then estimates a distance, a speed and anangle information of the target object with respect to the vehicle radardevice 100 according to the data. An algorithm configured in the radarcontrol unit 130 includes the FFT, a beamforming and a CFAR (ConstantFalse Alarm Rate) steps, wherein the FFT step is configured to providethe distance and the speed information, the beamforming step isconfigured to estimate the angle and a position information, and theCFAR step is configured to detect the target object while the clutterand other noise existing.

In FIG. 1B and FIG. 4A, the operating frequency of the first antennaarray 151 and the operating frequency of the second antenna array 152may be both greater than 10 GHz. Each of the first transmitting elements161, each of the first receiving elements 171, each of the secondtransmitting elements 162 and each of the second receiving elements 172is the microstrip antenna extending along the horizontal direction ofthe vehicle 40 and has the length smaller than 40 mm. Therefore, it isadvantageous in reducing the number of the vehicle radar device 100equipped in the vehicle radar system 4000 and maintaining the sameapplications and functions.

In an embodiment according to the present disclosure, the firsttransmitting elements, the first receiving elements, the secondtransmitting elements and the second receiving elements may be circuitboard antennas, which may be microstrip antennas specifically, e.g.slots antenna, patch antennas, microstrip shape antennas or combantennas extending along a horizontal direction or a vertical directionof a vehicle. Alternately, the first transmitting elements, the firstreceiving elements, the second transmitting elements and the secondreceiving elements may not be circuit board antennas, e.g. dishantennas. Moreover, types of the first transmitting elements, the firstreceiving elements, the second transmitting elements and the secondreceiving elements are not limited thereto, and the following conditionsare satisfied: 0 degrees<T12≤90 degrees; and 0 degrees<R12≤90 degrees.

In FIG. 4A, the vehicle radar system 4000 includes two vehicle radardevices, i.e. vehicle radar devices 100 and 100 a, which arerespectively disposed at the left-rear corner 49L and the right-rearcorner 49R of the vehicle 40, and located inside the bumper fascia. Thefirst circuit board 181 included in the vehicle radar device 100 and afirst circuit board 181 a included in the vehicle radar device 100 aface a left direction and a right direction of the vehicle 40,respectively, and are disposed symmetrically relative to a longitudinalcenterline y of the vehicle 40. That is, first transceiver units 141 and141 a, which are included in the vehicle radar devices 100 and 100 a,respectively, are configured to respectively detect a left environmentand a right environment of the vehicle 40, and also both detect a rearenvironment of the vehicle 40. The second circuit board 182 included inthe vehicle radar device 100 and a second circuit board 182 a includedin the vehicle radar device 100 a both face a rear direction of thevehicle 40 and are disposed symmetrically relative to the longitudinalcenterline y of the vehicle 40. That is, second transceiver units 142and 142 a, which are included in the vehicle radar devices 100 and 100a, respectively, are both configured to detect the rear environment ofthe vehicle 40. Accordingly, the vehicle radar system 4000 can providethe detection information of the left direction, the right direction andthe rear direction of the vehicle 40 so as to achieve the functions ofBSD (Blind Spot Detection), LCA (Lane Change Assistance) and reversedetection of the vehicle 40 via a single device set (i.e. the vehicleradar devices 100 and 100 a).

Specifically, the vehicle radar device 100 a disposed at the right-rearcorner 49R of the vehicle 40 includes the radar control unit 130 a, thefirst transceiver unit 141 a, the second transceiver unit 142 a, thefirst circuit board 181 a, the second circuit board 182 a and the thirdcircuit board 183 a. The first transceiver unit 141 a is communicativelyconnected to the radar control unit 130 a and includes a first antennaarray 151 a. The second transceiver unit 142 a is communicativelyconnected to the radar control unit 130 a and includes a second antennaarray 152 a. The first circuit board 181 a is vertical to the horizontaldirection of the vehicle 40. The first antenna array 151 a is aplurality of circuit board antennas and disposed on the first circuitboard 181 a. The second circuit board 182 a is vertical to thehorizontal direction of the vehicle 40. The second antenna array 152 ais a plurality of circuit board antennas and disposed on the secondcircuit board 182 a. The radar control unit 130 a is disposed on thethird circuit board 183 a. Only the second circuit board 182 a of thefirst circuit board 181 a and the second circuit board 182 a is parallelto the third circuit board 183 a. In addition, the first circuit board181 a, the second circuit board 182 a and the third circuit board 183 aare all disposed in a housing 140 a, which includes a connector 144 a.In brief, the vehicle radar device 100 a may be featured the same asthose of the vehicle radar device 100, which are recited in theaforementioned 1st and 4th embodiments. The vehicle radar devices 100and 100 a may be different devices, and the physical structuresrespectively of the vehicle radar devices 100 and 100 a aresymmetrically relative to the longitudinal centerline y of the vehicle40. Alternately, the vehicle radar devices 100 and 100 a may be the samedevices, and the physical structures respectively of the vehicle radardevices 100 and 100 a are symmetrically relative to the longitudinalcenterline y of the vehicle 40.

In FIG. 4B, the vehicle radar device 100 a may be communicativelyconnected to a vehicle control unit 43 of the vehicle 40 via the vehicleradar device 100. Accordingly, the control and the interface design ofthe vehicle radar system 4000 being simplified are beneficial to beintegrated with the vehicle control unit 43 and equipped in the vehicle40. Regarding the vehicle radar system 4000 in the 4th embodiment, thevehicle radar device 100 acts as a master radar, the vehicle radardevice 100 a acts as a slave radar, and the vehicle radar device 100 ais communicatively connected to the vehicle control unit 43 of thevehicle 40 via the vehicle radar device 100. The vehicle radar device100 and the vehicle control unit 43 may be communicatively connected byCAN (Controller Area Network), and the vehicle radar device 100 and 100a may be communicatively connected by CAN. In addition, the vehicleradar system 4000 may further include an alarm device 4400communicatively connected to the vehicle radar device 100 by a wiredmanner or a wireless manner. The alarm device 4400 is configured togenerate alarm signals to remind a driver of the vehicle 40 when thevehicle 40 satisfies emergency conditions. The alarm device 4400 may bea speaker, a buzzer, a display, or a light indicator to remind thedriver by a sound or light manner, but not limited thereto.

In FIG. 4B and FIG. 4C, the radar control units 130 and 130 arespectively include switching circuits 133 and 133 a configured toswitch the first transceivers units 141, 141 a or the second transceiverunits 142, 142 a to be in a detection mode. Only the first transceiverunits 141, 141 a are in the detection mode when the vehicle 40 is in aforward state (e.g. D gear of a gear selection unit 45 being selected),so that the detection information of the left direction, the rightdirection and the rear direction of the vehicle 40 can be provided toachieve the BSD and LCA functions of the vehicle 40. Only the secondtransceiver units 142, 142 a are in the detection mode when the vehicle40 is in a reverse state (e.g. R gear of the gear selection unit 45being selected), so that the detection information of the rear directionof the vehicle 40 can be provided to achieve the reversing detectionfunction of the vehicle 40. Therefore, the vehicle 40 is advantageous inswitching the first transceivers units 141, 141 a or the secondtransceiver units 142, 142 a to be in the detection mode according tothe forward state or the reverse state thereof.

FIG. 4G is a schematic view of the first transceiver units 141 and 141 ain the detection mode according to the 4th embodiment. In FIG. 4A andFIG. 4G, the first transceiver units 141 and 141 a both have angles ofarrival (AOA) above 30 degrees and detection distances between 50 m and70 m. When the vehicle radar devices 100 and 100 a are applied to theBSD function of the vehicle 40, based on a relative position and arelative speed of a moving object (or the target vehicle) with respectto the vehicle 40, it would be determined if the moving object is withina blind zone of the vehicle 40, and the driver would be timely remindedthe risks associated with changing lanes and other movements. When thevehicle radar devices 100 and 100 a are applied to the LCA function ofthe vehicle 40, the vehicle radar devices 100 and 100 a are configuredto compute the movement information of the moving objects in the left,right and rear directions and obtain the current state (e.g. the forwardstate or the reverse state) of the vehicle 40, and then the alarm device4400 would remind the driver to aid to determine the lane change timingto prevent from the traffic accident caused by the lane change.

In detail, when the vehicle radar devices 100 and 100 a are applied tothe BSD and LCA functions of the vehicle 40, the operation frequencythereof is about 77 GHz or 79 GHz, and a voltage range thereof is 9 V to16 V. The BSD mode can be triggered or activated to enable the firsttransceiver units 141 and 141 a when the vehicle 40 is in the forwardstate, or the BSD mode can be activated while the vehicle 40 being inthe forward state and a vehicle speed being greater than 10 kphcalculated by a vehicle speed calculation unit 46. When the vehicleradar devices 100 and 100 a are applied to the LCA function of thevehicle 40, the LCA mode can be activated while the BSD mode beingactivated and the vehicle speed being greater than 20 kph. The BSD modecan be terminated and followed by the LCA mode being terminated, whilethe vehicle 40 being in the reverse mode or the vehicle speed beingsmaller than 10 kph. Therefore, the vehicle radar system 4000 areadvantageous in detecting multiple target vehicles (e.g. target vehicles81 and 82) to analyze the distance and speed information with respect tothe vehicle 40 so as to obtain information of TTC (Time-to-Collision)between each target vehicle and the vehicle 40. One target vehicleclosest to the vehicle 40 among the target vehicles, which reach a TTCthreshold (Le. one of first emergency conditions), acts as an alarmtarget, and then the alarm device 4400 generates the alarm signal toremind the driver.

In addition, when the vehicle radar devices 100 and 100 a are applied tothe LCA function of the vehicle 40, an alarm threshold (another of thefirst emergency conditions, which causes the alarm device 4400 togenerate the alarm signal) of a rear side of the vehicle 40 beingapproached by the target vehicle is TTC 5 seconds, and a distance rangeof 35 m to 10 m between the target vehicle and the rear side of thevehicle 40 or a distance range of 0.5 m to 5 m between the targetvehicle and a left side or a right side of the vehicle 40. Theconditions of the alarm device 4400 stopping the alarm signal are adistance range of 10 m to 25 m between the target vehicle and the leftside or the right side of the vehicle 40 and the vehicle 40 beingapproached by the target vehicle with TTC>2 seconds, or a distance beinggreater than 20 m between the target vehicle and the rear side of thevehicle 40, or a distance being greater than 3 m between the targetvehicle and the left side or the right side of the vehicle 40. The LCAmode is terminated while the vehicle 40 being in the reverse mode or thevehicle speed being smaller than 20 kph. The LCA mode being terminatedfollows the BSD mode being terminated.

FIG. 4H is a schematic view of the parameters NT2 and WT2 according tothe 4th embodiment. In FIG. 1A, FIG. 4A and FIG. 4H, the secondtransmitting elements 162 of the vehicle radar device 100 may be thesecond narrow-angle transmitting elements 160 and the second wide-angletransmitting elements 166, and the radar control unit 130 is forswitching the second narrow-angle transmitting elements 160 or thesecond wide-angle transmitting elements 166 to operate. The secondreceiving elements 172 of the vehicle radar device 100 may be the secondnarrow-angle receiving elements 170 and the second wide-angle receivingelements 177, and the radar control unit 130 is for switching the secondnarrow-angle receiving elements 170 or the second wide-angle receivingelements 177 to operate. The second transmitting elements of the vehicleradar device 100 a may be a plurality of second narrow-angletransmitting elements and a plurality of second wide-angle transmittingelements (not shown in drawings), and the radar control unit 130 a isfor switching the second narrow-angle transmitting elements or thesecond wide-angle transmitting elements to operate. The second receivingelements of the vehicle radar device 100 a may be a plurality of secondnarrow-angle receiving elements and a plurality of second wide-anglereceiving elements (not shown in drawings), and the radar control unit130 a is for switching the second narrow-angle receiving elements or thesecond wide-angle receiving elements to operate.

When the second transceiver units 142 and 142 a are in the detectionmode, an angle of a central blind zone (its reference numeral isomitted) defined by the radiation pattern of the second narrow-anglereceiving element 170 disposed at the left-rear corner 49L and theradiation pattern of the second narrow-angle receiving element disposedat the right-rear corner 49R is NT2, that is, the central blind zone isformed between angles of arrival of horizontal plans of theaforementioned second narrow-angle receiving elements. The parameter NT2is as showing in FIG. 4H and has a value about 80 degrees. An angle of acentral blind zone (its reference numeral is omitted) defined by theradiation pattern of the second wide-angle receiving element 177disposed at the left-rear corner 49L and the radiation pattern of thesecond wide-angle receiving element disposed at the right-rear corner49R is WT2, That is, the central blind zone is formed between angles ofarrival of horizontal plans of the aforementioned second wide-anglereceiving elements. The parameter WT2 is as showing in FIG. 4H and has avalue about 140 degrees. Thus, the vehicle radar system 4000 of the 4thembodiment may satisfy the following conditions: 15 degrees≤NT2≤120degrees; and 60 degrees≤WT2≤175 degrees. Therefore, the radar controlunits 130 and 130 a would switch from the second narrow-angletransmitting/receiving elements (middle and short range antennas) to thesecond wide-angle transmitting/receiving elements (short range antennas)along with an obstruct approaching the rear side of the vehicle 40 so asto accurately detect the obstruct behind the vehicle 40. Furthermore,signals generated by the second antenna arrays 152 and 152 a form anintersection network. The central blind zone is formed out of theintersection network. When the angles of the central blind zones arelarger, the detection coverages are larger.

Moreover, the conventional ultrasonic radar usually has smallerdetection angle, and thereby multiple conventional ultrasonic radars arerequired (four radars required generally) to be equipped to coverage therear area of the vehicle. The vehicle radar devices 100 and 100 aaccording to the present disclosure are millimeter wave radars, it isbeneficial to apparently improve the detection problems resulted fromblind zone and adjust the detection angles via the design of the secondantenna arrays 152 and 152 a (or the second circuit boards 182 and 182a). Thus, the vehicle radar devices 100 and 100 a respectively disposedat the left-rear corner 49L and the right-rear corner 49R can coveragethe rear detection of the vehicle 40 so as to prevent the bumper frombeing punched and reduce time and manpower during installing.

A transmitting signal of the second transceiver units 142 and 142 a maybe generated with at least one of a time division multiplexing manner, afrequency division multiplexing manner and an orthogonal signal mannercontrolled by the radar control units 130 and 130 a. Therefore, thesecond transceiver units 142 and 142 a can be effectively prevented fromdetection interference caused by a rear overlapping zone of the vehicle40.

When the vehicle radar devices 100 and 100 a are applied to thereversing detection function of the vehicle 40, the operation frequencythereof is about 77 GHz or 79 GHz, and a voltage range thereof is 9 V to16 V. The reversing detection mode can be triggered or activated toenable the second transceiver units 142 and 142 a when the vehicle 40 isin the reverse state, or the reversing detection mode can be activatedwhile the vehicle 40 being in the reverse state and the vehicle speedbeing smaller than 8 kph calculated by the vehicle speed calculationunit 46. When second emergency condition related to the distance, thevehicle speed or TTC is satisfied, the alarm device 4400 generates analarm signal. The radar control units 130 and 130 a would switch fromthe second narrow-angle transmitting/receiving elements (middle andshort range antennas, long detection distance, and long alarm distance)to the second wide-angle transmitting/receiving elements (short rangeantennas, short detection distance, and short alarm distance) along withan obstruct approaching the rear side of the vehicle 40 so as toaccurately detect the obstruct behind the vehicle 40.

FIG. 5A is a block diagram of a vehicle radar system 5000 according tothe 5th embodiment of the present disclosure, which is disposed in avehicle 50. FIG. 5B is a block diagram of the vehicle radar system 5000according to the 5th embodiment. In FIG. 2, FIG. 5A and FIG. 5B, thevehicle radar system 5000 is disposed in the vehicle 50 and includes twovehicle radar devices, i.e. vehicle radar devices 200 a and 200 recitedin the aforementioned 2nd embodiment, which are respectively disposed ata left-rear corner and a right-rear corner of the vehicle 50. Thevehicle radar device 200 a may be featured the same as those of thevehicle radar device 200, which are recited in the aforementioned 2ndembodiment.

The vehicle radar device 200 includes the radar control unit 230, afirst transceiver unit 241 and a second transceiver unit 242. The firsttransceiver unit 241 is communicatively connected to the radar controlunit 230 and includes the first antenna array 251, and the secondtransceiver unit 242 is communicatively connected to the radar controlunit 230 and includes the second antenna array 252. The vehicle radardevice 200 a includes a radar control unit 230 a, a first transceiverunit 241 a and a second transceiver unit 242 a. The first transceiverunit 241 a is communicatively connected to the radar control unit 230 aand includes a first antenna array (not shown in drawings), and thesecond transceiver unit 242 a is communicatively connected to the radarcontrol unit 230 a and includes a second antenna array (not shown indrawings). Specifically, each unit of the first transceiver units 241,241 a and the second transceiver units 242, 242 a is in a detection modewhen the vehicle 50 is in the start state. The radar control units 230,230 a are configured to determine if the vehicle 50 satisfies a firstemergency condition (e.g. the first emergency condition recited in the4th embodiment) in accordance with data from the first transceiver units241, 241 a. The radar control units 230, 230 a are also configured todetermine and if the vehicle 50 satisfies a second emergency condition(e.g. the second emergency condition recited in the 4th embodiment) inaccordance with data from the second transceiver units 242, 242 a. Thevehicle radar system 5000 further includes an alarm device 5400communicatively connected to the radar control units 230, 230 a(specifically, the alarm device 5400 is communicatively connected to theradar control unit 230 a via the radar control unit 230). The alarmdevice 5400 is controlled by the radar control units 230, 230 a togenerate an alarm signal when the vehicle 50 is in a forward stateaccording to data of a vehicle control unit 53, a gear selection unit 55and a vehicle speed calculation unit 56 and satisfies the firstemergency condition, and the alarm device 5400 is controlled by theradar control units 230, 230 a to generate another alarm signal when thevehicle 50 is in a reverse state and satisfies the second emergencycondition. Therefore, all of the first transceiver units 241, 241 a andthe second transceiver units 242, 242 a transmit and receive signals,i.e. continue to operate, when the vehicle 50 is in the start state,instead of being activated based on the gear selection. Furthermore, analarm signal associated to the BSD, LCA functions or an alarm signalassociated to the reversing detection function can be selected togenerate by the alarm device 5400 according to the gear selection, sothat a switching circuit for switching among transceiver units or amongantenna channels (selecting first antenna array or second antenna array)can be omitted.

In addition, regarding the vehicle radar system 5000 of the 5thembodiment, except the characteristics recited in the last paragraphbeing different from the characteristics recited in the aforementioned4th embodiment, the other characteristics of the vehicle radar system5000 may be the same as the corresponding characteristics of the vehicleradar system 4000.

Although the present disclosure has been described in considerabledetail with reference to certain embodiments thereof, other embodimentsare possible. Therefore, the spirit and scope of the appended claimsshould not be limited to the description of the embodiments containedherein. It will be apparent to those skilled in the art that variousmodifications and variations can be made to the structure of the presentdisclosure without departing from the scope or spirit of the disclosure.In view of the foregoing, it is intended that the present disclosurecover modifications and variations of this disclosure provided they fallwithin the scope of the following claims.

What is claimed is:
 1. A vehicle radar device, comprising: a radarcontrol unit; a first antenna array communicatively connected to theradar control unit, wherein the first antenna array comprises aplurality of first transmitting elements and a plurality of firstreceiving elements; a second antenna array communicatively connected tothe radar control unit, wherein the second antenna array comprises aplurality of second transmitting elements and a plurality of secondreceiving elements; a first circuit board, wherein the first antennaarray is a plurality of circuit board antennas and disposed on the firstcircuit board; and a second circuit board, wherein the second antennaarray is a plurality of circuit board antennas and disposed on thesecond circuit board; wherein an angle between the first circuit boardand the second circuit board is P12, and the following condition issatisfied: 60 degrees≤P12<180 degrees.
 2. The vehicle radar device ofclaim 1, further comprising: a third circuit board, wherein the radarcontrol unit is disposed on the third circuit board, and only one of thefirst circuit board and the second circuit board is parallel to thethird circuit board.
 3. The vehicle radar device of claim 1, wherein anoperating frequency of the first antenna array and an operatingfrequency of the second antenna array are both greater than 10 GHz, andeach of the first transmitting elements, each of the first receivingelements, each of the second transmitting elements and each of thesecond receiving elements is a microstrip antenna and has a lengthsmaller than 40 mm.
 4. The vehicle radar device of claim 1, wherein thesecond transmitting elements are a plurality of second narrow-angletransmitting elements and a plurality of second wide-angle transmittingelements, the radar control unit is for switching the secondnarrow-angle transmitting elements or the second wide-angle transmittingelements to operate, the second receiving elements are a plurality ofsecond narrow-angle receiving elements and a plurality of secondwide-angle receiving elements, and the radar control unit is forswitching the second narrow-angle receiving elements or the secondwide-angle receiving elements to operate.
 5. A vehicle radar system,disposed in a vehicle and comprising at least one vehicle radar device,the at least one vehicle radar device comprising: a radar control unit;a first transceiver unit communicatively connected to the radar controlunit and comprising a first antenna array, wherein the first antennaarray comprises a plurality of first transmitting elements and aplurality of first receiving elements; and a second transceiver unitcommunicatively connected to the radar control unit and comprising asecond antenna array, wherein the second antenna array comprises aplurality of second transmitting elements and a plurality of secondreceiving elements; wherein an angle between a centerline of ahorizontal main lobe of the first transmitting elements and a centerlineof a horizontal main lobe of the second transmitting elements is T12, anangle between a centerline of a horizontal main lobe of the firstreceiving elements and a centerline of a horizontal main lobe of thesecond receiving elements is R12, and the following conditions aresatisfied: 0 degrees<T12≤90 degrees; and 0 degrees<R12≤90 degrees. 6.The vehicle radar system of claim 5, wherein the at least one vehicleradar device further comprises: a first circuit board, wherein the firstantenna array is a plurality of circuit board antennas and disposed onthe first circuit board; and a second circuit board, wherein the secondantenna array is a plurality of circuit board antennas and disposed onthe second circuit board.
 7. The vehicle radar system of claim 6,wherein the at least one vehicle radar device further comprises: a thirdcircuit board, wherein the radar control unit is disposed on the thirdcircuit board, and only one of the first circuit board and the secondcircuit board is parallel to the third circuit board.
 8. The vehicleradar system of claim 6, wherein an operating frequency of the firstantenna array and an operating frequency of the second antenna array areboth greater than 10 GHz, and each of the first transmitting elements,each of the first receiving elements, each of the second transmittingelements and each of the second receiving elements is a microstripantenna extending along a horizontal direction of the vehicle and has alength smaller than 40 mm.
 9. The vehicle radar system of claim 6,wherein a number of the at least one vehicle radar device is two, thetwo vehicle radar devices are respectively disposed at a left-rearcorner and a right-rear corner of the vehicle, the two first circuitboards respectively of the two vehicle radar devices face a leftdirection and a right direction of the vehicle, respectively, and aredisposed symmetrically relative to a longitudinal centerline of thevehicle, and the two second circuit boards respectively of the twovehicle radar devices both face a rear direction of the vehicle and aredisposed symmetrically relative to the longitudinal centerline of thevehicle.
 10. The vehicle radar system of claim 9, wherein the secondtransmitting elements of each of the two vehicle radar devices are aplurality of second narrow-angle transmitting elements and a pluralityof second wide-angle transmitting elements, each of the two radarcontrol units respectively of the two vehicle radar devices is forswitching the second narrow-angle transmitting elements or the secondwide-angle transmitting elements to operate, the second receivingelements of each of the two vehicle radar devices are a plurality ofsecond narrow-angle receiving elements and a plurality of secondwide-angle receiving elements, and each of the two radar control unitsis for switching the second narrow-angle receiving elements or thesecond wide-angle receiving elements to operate; wherein an angle of acentral blind zone defined by radiation patterns of the secondnarrow-angle receiving elements of the two vehicle radar devicesrespectively disposed at the left-rear corner and the right-rear corneris NT2, an angle of a central blind zone defined by radiation patternsof the second wide-angle receiving elements of the two vehicle radardevices respectively disposed at the left-rear corner and the right-rearcorner is WT2, and the following conditions are satisfied: 15degrees≤NT2≤120 degrees; and 60 degrees≤WT2≤175 degrees.
 11. The vehicleradar system of claim 9, wherein a transmitting signal of the two secondtransceiver units respectively of the two vehicle radar devices isgenerated with at least one of a time division multiplexing manner, afrequency division multiplexing manner and an orthogonal signal mannercontrolled by the two radar control units respectively of the twovehicle radar devices.
 12. The vehicle radar system of claim 9, whereinone of the two vehicle radar devices is communicatively connected to avehicle control unit of the vehicle via the other one of the two vehicleradar devices.
 13. The vehicle radar system of claim 9, wherein theradar control unit of each of the two vehicle radar devices comprises: aswitching circuit configured to switch the first transceiver unit or thesecond transceiver unit to be in a detection mode, wherein only thefirst transceiver unit is in the detection mode when the vehicle is in aforward state, and only the second transceiver unit is in the detectionmode when the vehicle is in a reverse state.
 14. The vehicle radarsystem of claim 9, wherein each unit of the two first transceiver unitsand the two second transceiver units of the two vehicle radar devices isin a detection mode when the vehicle is in a start state, the two radarcontrol units respectively of the two vehicle radar devices areconfigured to determine if the vehicle satisfies a first emergencycondition in accordance with data from the two first transceiver unitsrespectively of the two vehicle radar devices, and if the vehiclesatisfies a second emergency condition in accordance with data from thetwo second transceiver units respectively of the two vehicle radardevices; wherein the vehicle radar system further comprises an alarmdevice communicatively connected to the two radar control units, thealarm device is controlled by the two radar control units to generate analarm signal when the vehicle is in a forward state and satisfies thefirst emergency condition, and the alarm device is controlled by the tworadar control units to generate another alarm signal when the vehicle isin a reverse state and satisfies the second emergency condition.
 15. Thevehicle radar system of claim 5, wherein a half power beam width of thehorizontal main lobe of the first receiving elements is RA1, and thefollowing condition is satisfied: 75 degrees≤RA1<180 degrees.
 16. Thevehicle radar system of claim 5, wherein the angle between thecenterline of the horizontal main lobe of the first receiving elementsand the centerline of the horizontal main lobe of the second receivingelements is R12, and the following condition is satisfied: 15degrees≤R12≤75 degrees.
 17. A vehicle radar system, disposed in avehicle and comprising at least one vehicle radar device, the at leastone vehicle radar device disposed at one of four corners of the vehicleand comprising: a radar control unit; a first antenna arraycommunicatively connected to the radar control unit; a second antennaarray communicatively connected to the radar control unit; a firstcircuit board vertical to a horizontal direction of the vehicle, whereinthe first antenna array is a plurality of circuit board antennas anddisposed on the first circuit board; and a second circuit board verticalto the horizontal direction of the vehicle, wherein the second antennaarray is a plurality of circuit board antennas and disposed on thesecond circuit board; wherein an angle between the first circuit boardand the second circuit board is P12, and the following condition issatisfied: 90 degrees≤P12<180 degrees.
 18. The vehicle radar system ofclaim 17, wherein a number of the at least one vehicle radar device istwo, the two vehicle radar devices are respectively disposed at aleft-rear corner and a right-rear corner of the four corners of thevehicle, the two first circuit boards respectively of the two vehicleradar devices face a left direction and a right direction of thevehicle, respectively, and are disposed symmetrically relative to alongitudinal centerline of the vehicle, and the two second circuitboards respectively of the two vehicle radar devices both face a reardirection of the vehicle and are disposed symmetrically relative to thelongitudinal centerline of the vehicle.
 19. The vehicle radar system ofclaim 18, wherein the second antenna array of each of the two vehicleradar devices comprises a plurality of second transmitting elements anda plurality of second receiving elements, the second transmittingelements are a plurality of second narrow-angle transmitting elementsand a plurality of second wide-angle transmitting elements, each of thetwo radar control units respectively of the two vehicle radar devices isfor switching the second narrow-angle transmitting elements or thesecond wide-angle transmitting elements to operate, the second receivingelements of each of the two vehicle radar devices are a plurality ofsecond narrow-angle receiving elements and a plurality of secondwide-angle receiving elements, and each of the two radar control unitsis for switching the second narrow-angle receiving elements or thesecond wide-angle receiving elements to operate; wherein an angle of acentral blind zone defined by radiation patterns of the secondnarrow-angle receiving elements of the two vehicle radar devicesrespectively disposed at the left-rear corner and the right-rear corneris NT2, an angle of a central blind zone defined by radiation patternsof the second wide-angle receiving elements of the two vehicle radardevices respectively disposed at the left-rear corner and the right-rearcorner is WT2, and the following conditions are satisfied: 15degrees≤NT2≤120 degrees; and 60 degrees≤WT2≤175 degrees.
 20. The vehicleradar system of claim 17, wherein the angle between the first circuitboard and the second circuit board is P12, and the following conditionis satisfied: 105 degrees≤P12≤165 degrees.